[Bug 2084] R-094: Issues with identity constraints and derivation by restriction

http://www.w3.org/Bugs/Public/show_bug.cgi?id=2084

           Summary: R-094: Issues with identity constraints and derivation
                    by restriction
           Product: XML Schema
           Version: 1.0
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: XSD Part 1: Structures
        AssignedTo: ht@w3.org
        ReportedBy: sandygao@ca.ibm.com
         QAContact: www-xml-schema-comments@w3.org


In the section titled 'Schema Component Constraint: Particle Restriction OK 
(Elt:Elt -- NameAndTypeOK)', the following is mentioned:

"For an element declaration particle to be a valid restriction of another 
element declaration particle all of the following must be true:

5 R's declaration's {identity-constraint definitions} is a subset of B's 
declaration's {identity-constraint definitions}, if any." 

The issues are: 

the spec should be clarified to state what "subset" means 
the subset requirement runs the wrong way -- the derived element's IC's should 
be a _super_set of the base's. 
an element decl in a restriction can't have the same ICs as its corresponding 
decl in the base, because that would violate the named-components-are-unique 
constraint 
The original questions were posted to the schema-dev list. Henry summarized the 
issues in the following mail on schema-comments: 
http://lists.w3.org/Archives/Public/www-xml-schema-comments/2001OctDec/0187.html

and:
http://lists.w3.org/Archives/Public/www-xml-schema-comments/2001OctDec/0188.html

Received on Friday, 9 September 2005 03:22:14 UTC